Structural Chemistry of Bismuth Compounds. I. Organobismuth Derivatives

Silvestru, Cristian; Breunig, H. J.; Althaus, Henrik

doi:10.1021/cr980083q

Cited by 218 publications

(174 citation statements)

References 181 publications

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“…Compared to Re-Bi compounds [2, 13, 17 -19], more literature is available on complexes containing Fe-Bi bonds [20,21]. The focus of our work was again on bismuthanes bearing a bismuth atom connected to organoiron fragments, such as η 5 -cyclopentadienyl dicarbonyl iron [Cp(CO) 2 perature for a period of 72 h resulted in a bright-orange suspension, which was concentrated to one third of the volume.…”

Section: Complex Synthesis and Characterizationmentioning

confidence: 99%

Heterometallic Complexes with Rhenium- and Iron-Bismuth Bonds

Schiwon

Metzinger

Pfirrmann

et al. 2013

Zeitschrift Für Naturforschung B

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Section: Complex Synthesis and Characterizationmentioning

confidence: 99%

Heterometallic Complexes with Rhenium- and Iron-Bismuth Bonds

Schiwon

Metzinger

Pfirrmann

et al. 2013

Zeitschrift Für Naturforschung B

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“…From the results, it is clear that a Lewis acid was necessary, although the best results were obtained when the bismuth salt was present. The improvement obtained when bismuth was present may be due to its high affinity for chlorine, as has been shown in many x-ray structures of chloride derivatives [18]. …”

mentioning

confidence: 84%

The First Synthesis of p-Cl- and p-F-Phenylverbenene

Contreras-Celedón¹,

Chacón-Garcı́a

2008

TOOCJ

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Abstract:The first synthesis of 4´-X-phenylverbenene (X = F and Cl) via reaction of myrtenal with 4 -X phenylmagnesium bromide and Bi(NO 3 ) 3 is described. Verbenene is formed due to the electron-withdrawing effect of the 4 -electronegative group, either fluorine or a Cl-Bi complex.Keywords: Myrtenal, verbenene, bismuth nitrate, pinane, lewis acid.In recent years, bismuth compounds have attracted great interest in organic synthesis. Although their chemistry is not well known, bismuth salts have been widely used as Lewis acids to catalyze numerous reactions, mainly functional group deprotections, oxidations, reductions, rearrangements and C-C bond formation [1]. The last of these reactions can be achieved by Friedel-Crafts acylation, aldolic and Knoevenagel condensations, Diels-Alder cycloaddition, and Michael addition, to mention just a few possibilities [2]. Recently, bismuth has also been used in the chemistry of natural products [3]. Studies on the chemistry of natural products of pinene derivatives have increased in recent years because of the wide biological activity that this group of compounds presents. One of these derivatives is verbenene 2 (Fig. 1), which is found as a secondary metabolite in many medicinal plants and has been investigated as a beetle attractor [4,5]. Verbenene has also been used in the study of cycloadditions on account of its restricted stereochemistry and can also be viewed as a precursor in the formal synthesis of verbenone, which can provide a possible starting point in the synthesis of the A ring of taxol and other interesting compounds [6][7][8][9][10]. Verbenene has been synthesized through an electron transfer from -or -pinene to 2,3,5,6-tetrachlorobenzoquinone on sensitized irradiation where a radical cation rapidly deprotonates to give verbenene with retention of chirality [11]. To study the mechanism of bismuth-catalyzed additions to double bond carbonyl-activated systems, in the present work we examined the addition of Grignard reagents to myrtenal 1 catalyzed by Bi(NO 3 ) 3 . We found no difference in diastereoselectivity, but surprisingly observed the production of phenylverbenenes 3c and 3d in good yield when 4 -Cl-or 4 -F-phenylmagnesium bromide was added at 0°C (Scheme 1). Under the same conditions but in the presence of methyl iodide, alcohols 4 and 5 (c and d) give 3 (c and d respectively) in 98% yield (Scheme 1). RESULTS AND DISCUSSIONWe used (1R)-(-)-myrtenal as a model system because some of its derivatives are good chiral auxiliaries that induce high enantiomeric excess because of the conformational restriction that is present in the bicyclic system [12][13][14][15][16]. Results of the addition of 4 -MeO-, 4 -Cl-or 4 -F-PhMgBr to myrtenal in the presence or absence of bismuth(III) nitrate at three temperatures (0°C, 25°C and reflux) are listed in Table 1.The results show no significant difference in diastereoselectivity among the various reactions, and the bismuth salt does not have any effect on the reaction. Although no significant diastereoisomeric excess w...

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“…Além disso, compostos de bismuto exibem acidez de Lewis de moderada a forte devido à blindagem deficiente do núcleo pelos elétrons f do átomo de bismuto (Bi = [Xe] 4f 14 , 5d 10 , 6s 2 , 6p 3 ). [18][19][20][21][22][23][24] Por consequência, o comportamento catalítico destes compostos tem sido investigado em diferentes tipos de reações químicas, exceto em reações de transesterificação, onde sua aplicação catalítica ainda é desconhecida. Por outro lado, o sólido NaBiO 3 ·2H 2 O também é frequentemente utilizado na determinação de manganês em ferro e aço.…”

Section: Introductionunclassified

Avaliação da natureza da atividade catalítica de compostos de bismuto em reações de metanólise do óleo de soja

Silva¹,

Brugnago²,

Marangoni³

et al. 2012

Quím. Nova

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Recebido em 20/2/11; aceito em 28/5/11; publicado na web em 22/7/11 ASSESSMENT OF THE CATALYTIC PROPERTIES OF BISMUTH COMPOUNDS IN SOYBEAN OIL METHANOLYSIS. Sodium bismuthate dihydrate and two species derived from its thermal treatment were investigated as catalysts for soybean oil methanolysis and, regardless of the type of solid used, ester yields always above 76 wt% were obtained. After a single reaction course, both liquid and solid phases were characterized using several analytical methods such as X-ray diffraction and thermogravimetric analysis. As a result, the catalytic phenomenon was shown to be solely due to the leaching of alkalinecatalytic species from the solid materials.Keywords: biodiesel; bismuth; transesterification. INTRODUÇÃOA viscosidade dos óleos vegetais é cerca de 11 a 17 vezes maior que a do diesel de petróleo e esta propriedade dificulta o seu uso direto em motores de combustão por compressão interna (ciclo Diesel). Altas viscosidades causam a má atomização do combustível na câmara de combustão, gerando queimas parciais que resultam na formação de depósitos e gomas nos bicos injetores, nos cilindros e em outras partes internas do motor.1-4 Por esta razão, óleos vegetais in natura têm que ser pré-aquecidos para que o sistema de injeção opere normalmente e o motor apresente um desempenho adequado. 1Além disso, a combustão de triacilgliceróis também está associada à emissão de acroleína, substância tóxica e cancerígena que é formada pela decomposição térmica do glicerol. 5Em meados do século passado, a transesterificação de óleos vegetais foi proposta como uma possível solução para este problema. Nesta reação, metanol ou etanol podem ser utilizados como reagentes, na presença de um catalisador ácido, básico ou enzimático, para produzir monoésteres graxos cujas propriedades físicas e químicas são adequadas ao uso combustível em motores do ciclo Diesel.2 Este combustível, de origem renovável, foi então denominado biodiesel pelos órgãos reguladores e pela comunidade científica internacional. No entanto, outras classes de biocombustíveis também vêm sendo classificadas genericamente como biodiesel, tais como hidrocarbonetos derivados da biomassa (incluindo materiais graxos de diferentes origens) por processos térmicos. Atualmente, o craqueamento, o hidrocraqueamento (processo H-Bio) e o eletrocraqueamento são os processos que vêm sendo mais discutidos no âmbito do Programa Nacional de Produção e Uso do Biodiesel (PNPB). 6 Recentemente, a busca por processos industriais de maior viabilidade econômica tem levado ao desenvolvimento de rotas alternativas para a produção de ésteres graxos. Tais rotas estão baseadas na utilização de materiais de menor valor agregado, como óleos de frituras, gorduras residuais e óleos de descarte, que inevitavelmente possuem maior acidez. Por esta razão, a esterificação de ácidos graxos vem sendo identificada como uma importante alternativa para o setor, seja como procedimento para a correção da acidez de materiais graxos residuais ou como etapa de conversão dos ácidos...

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Structural Chemistry of Bismuth Compounds. I. Organobismuth Derivatives

Cited by 218 publications

References 181 publications

Heterometallic Complexes with Rhenium- and Iron-Bismuth Bonds

Heterometallic Complexes with Rhenium- and Iron-Bismuth Bonds

The First Synthesis of p-Cl- and p-F-Phenylverbenene

Avaliação da natureza da atividade catalítica de compostos de bismuto em reações de metanólise do óleo de soja

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